Gas turbine engine combustor

ABSTRACT

A gas turbine engine combustor includes a gas-turbine-engine-combustor outer annular case and a gas-turbine-engine-combustor premixer tube. The outer annular case has a longitudinal axis. The premixer tube has an entrance, an exit, and a centerline. The premixer tube is adapted to receive fuel-injector-discharged fuel. The entrance is adapted to receive at least some compressor-discharge air. The exit is located inside the outer annular case. At the exit the centerline points in a direction which is more perpendicular to, than parallel to, the longitudinal axis. In one example, the combustor is a straight-flow combustor. In a different example, the combustor is a reverse-flow combustor.

BACKGROUND OF THE INVENTION

The present invention relates generally to combustors, and more particularly to a gas turbine engine combustor.

Conventional gas turbine engine combustors have outer and inner annular cases, outer and inner liners (with air dilution holes) located radially between the outer and inner annular cases, a combustor dome connecting the outer and inner liners, and circumferentially arrayed premixer tubes each having an entrance and an exit. Each premixer tube is adapted to receive fuel-injector-discharged fuel, the entrance is adapted to receive at least some compressor-discharge air, and the exit is aligned to axially deliver such fuel-air mixture for ignition in the combustor. The combustion gases power a downstream turbine which rotates the compressor. Straight flow and reverse flow combustors are known. Gas turbine engines have been used to power aircraft, ships, etc.

Still, scientists and engineers continue to seek improved gas turbine engine combustors.

BRIEF DESCRIPTION OF THE INVENTION

A first expression of a first embodiment of the invention is a gas turbine engine combustor including a gas-turbine-engine-combustor outer annular case and a gas-turbine-engine-combustor premixer tube. The outer annular case has a longitudinal axis. The premixer tube has an entrance, an exit, and a centerline. The premixer tube is adapted to receive fuel-injector-discharged fuel. The entrance is adapted to receive at least some compressor-discharge air. The exit is located inside the outer annular case. At the exit the centerline points in a direction which is more perpendicular to, than parallel to, the longitudinal axis.

A second expression of a first embodiment of the invention is a gas turbine engine combustor including a straight-flow-combustor outer annular case and a gas-turbine-engine-combustor premixer tube. The outer annular case has a longitudinal axis. The premixer tube has an entrance, an exit, and a centerline. The premixer tube is adapted to receive fuel-injector-discharged fuel. The entrance is adapted to receive at least some compressor-discharge air. The exit is located inside the outer annular case. At the exit the centerline points in a direction which is more perpendicular to, than parallel to, the longitudinal axis. The direction is angled between generally sixty degrees and generally eighty degrees away from the longitudinal axis.

A first expression of a second embodiment of the invention is a gas turbine engine combustor including a reverse-flow-combustor outer annular case and a gas-turbine-engine-combustor premixer tube. The outer annular case has a longitudinal axis. The premixer tube has an entrance, an exit, and a centerline. The premixer tube is adapted to receive fuel-injector-discharged fuel. The entrance is adapted to receive at least some compressor-discharge air. The exit is located inside the outer annular case. At the exit the centerline points in a direction which is more perpendicular to, than parallel to, the longitudinal axis. The direction is angled between generally sixty degrees and generally eighty degrees away from the longitudinal axis.

In one example of any expression of any embodiment of the invention, use of a premixer tube whose centerline, at the exit of the premixer tube, points in a direction more perpendicular to, than parallel to, the longitudinal axis of the gas-turbine-engine-combustor outer annular case creates a swirled flow from the exit of the premixer tube. In this example, such swirled flow results in a shorter and simpler combustor design with fewer swirlers, lower soot, lower carbon monoxide, lower NOx, a greater turndown (e.g., 20:1), an excellent pattern factor (e.g., less than 0.20), and a lower cost compared to the axial flow from the exit of a premixer tube of a conventional gas-turbine-engine combustor.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate two embodiments of the invention wherein:

FIG. 1 is a schematic front elevational view looking downstream of a first embodiment of a gas turbine engine combustor, wherein the combustor is a straight-flow combustor, and includes a premixer tube and additional premixer tubes;

FIG. 2 is a schematic aft elevational view looking upstream of the combustor of FIG. 1;

FIG. 3 is a cross sectional view taken along lines 3-3 of FIG. 2 with the tubes not shown in cross section for clarity;

FIG. 4 is an enlarged cross sectional view of the premixer tube of the combustor of FIG. 1 with a fuel injector present;

FIG. 5 is a schematic cross sectional view of a second embodiment of a gas turbine engine combustor, wherein the combustor is a reverse-flow combustor, and includes a premixer tube with the tube not shown in cross section for clarity;

FIG. 6 is a cross-sectional view taken along lines 5-5 of FIG. 4 showing additional premixer tubes and with the fuel injectors omitted for clarity, and

FIG. 7 is an enlarged perspective view of the premixer tube of the combustor of FIG. 5 with a fuel injector present.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, FIGS. 1-4 disclose a first embodiment of the invention. A first expression of the embodiment of FIGS. 1-4 is for a gas turbine engine combustor 110 including a gas-turbine-engine-combustor outer annular case 112 and a gas-turbine-engine-combustor premixer tube 114. The outer annular case 112 has a longitudinal axis 116. The premixer tube 114 has an entrance 118, an exit 120, and a centerline 122. The premixer tube 114 is adapted to receive fuel-injector-discharged fuel 124. The entrance 118 is adapted to receive at least some compressor-discharge air 126. The exit 120 is disposed inside the outer annular case 112. At the exit 120 the centerline 122 points in a direction 128 which is more perpendicular to, than parallel to, the longitudinal axis 116.

In one enablement of the first expression of the first embodiment of FIGS. 1-4, the direction 128 is more perpendicular to, than along, a reference line 130 which extends from the centerline 122 at the exit 120 to the longitudinal axis 116. In one variation, the direction 128 is angled between generally sixty degrees and generally eighty degrees away from the longitudinal axis 116 (i.e., away from a line parallel to the longitudinal axis 116 and intersecting the centerline 122 at the exit 120), and the direction 128 is angled between generally sixty degrees and generally eighty degrees away from the reference line 130.

In one implementation of the first expression of the first embodiment of FIGS. 1-4, the combustor 110 also includes a gas-turbine-engine-combustor inner annular case 132, a gas-turbine-engine-combustor outer liner 134, and a gas-turbine-engine-combustor inner liner 136, wherein the outer and inner liners 134 and 136 are disposed radially between the outer and inner annular cases 112 and 132 and wherein the exit 120 is disposed radially between the outer and inner liners 134 and 136. In one variation, the combustor 110 also includes a plurality of gas-turbine-engine-combustor additional premixer tubes 138 substantially identical to the premixer tube 114, wherein the premixer and additional premixer tubes 114 and 138 are substantially circumferentially arrayed with a substantially equal circumferential distance between adjacent ones of the exits 120 of the premixer and additional premixer tubes 114 and 138. In one modification, the exits 120 of the premixer and additional premixer tubes 114 and 138 are disposed wherein ignition at one of the exits 120 of the premixer and additional premixer tubes 114 and 138 will cause ignition, in sequential rotation, at each of the other of the exits 120 of the premixer and additional premixer tubes 114 and 138.

In one application of the first expression of the first embodiment of FIGS. 1-4, the outer and inner liners 134 and 136 each include a plurality of air dilution holes 140. In one employment, the combustor 110 also includes a combustor dome 142 connecting the outer and inner liners 134 and 136. In one construction, the premixer tube 114 is a thermal-barrier-coated tube and the combustor dome 142 is a thermal-barrier-coated combustor dome.

In one deployment of the first expression of the first embodiment of FIGS. 1-4, some compressor-discharge air 144 also flows between the outer annular case 112 and the outer liner 134 and between the inner annular case 132 and the inner liner 136. In one variation, some of that compressor-discharge air 144 flows through the air dilution holes 140. In a gas turbine engine, a compressor (not shown) upstream of the combustor 110 supplies the compressor-discharge air 126 and 144 to the combustor 110 and combustion gases from the combustor 110 are channeled to a downstream turbine (not shown) which rotates the compressor as is known to those skilled in the art. Examples of uses of the combustor 110 include, without limitation, aircraft gas turbine engines, helicopter gas turbine engines, land-based gas turbine engines such as electric-power-plant gas turbine engines, and marine-base gas turbine engines such as ship-propulsion gas turbine engines, etc. In one arrangement, the premixer tube 114 is equipped with some swirlers (not shown). In one arrangement, a fuel injector 146 discharges fuel in the premixer tube 114 proximate the exit 120. Fuel types include natural and/or synthetic liquid fuels and/or natural and/or synthetic gaseous fuels.

Designs of the first expression of the first embodiment of FIGS. 1-4 include straight flow and reverse flow can types and straight flow and reverse flow non-can type combustor arrangements. In one non-can type combustor arrangement, a gas turbine engine has a single combustor (annular combustor) whose centerline is substantially coaxial with the compressor and turbine centerlines. In one can type combustor arrangement, a gas turbine engine has a plurality of annularly arrayed can combustors (can-annular combustors) whose centerlines are angled with respect to the compressor and turbine centerlines. It is noted that each premixer tube of a combustor need not be of the same size and/or operate at the same fuel-to-air ratio and/or receive the same amount of compressor-discharged air.

In one example of the first expression of the first embodiment of FIGS. 1-4, the direction 128 forms an angle less than generally thirty degrees to a plane (the plane of the paper in FIG. 2) which is perpendicular to the longitudinal axis 116 and passes through the centerline 122 at the exit 120, and the direction 128 forms an angle less than generally thirty degrees to a tangent at a point on a circle which passes through the intersection of the centerline 122 and the exit 120 of the premixer and additional premixer tubes 114 and 138) wherein the point is such intersection.

It is noted that the first combustor embodiment of FIGS. 1-4 illustrates an embodiment of a straight-flow combustor, that the second combustor embodiment of FIGS. 5-7 illustrates an embodiment of a reverse-flow combustor, and that the above description of the first embodiment is equally applicable to describing the second embodiment with the substitution of the 200 series of part numbers shown in FIGS. 5-7 in place of the 100 series of part numbers shown in FIGS. 1-4.

A second expression of the first embodiment of FIGS. 1-4 is for a gas turbine engine combustor 110 including a straight-flow-combustor outer annular case 112′ and a gas-turbine-engine-combustor premixer tube 114. The outer annular case 112′ has a longitudinal axis 116. The premixer tube 114 has an entrance 118, an exit 120, and a centerline 122. The premixer tube 114 is adapted to receive fuel-injector-discharged fuel 124. The entrance 118 is adapted to receive at least some compressor-discharge air 126. The exit 120 is disposed inside the outer annular case 112′. At the exit 120 the centerline 122 points in a direction 128 which is more perpendicular to, than parallel to, the longitudinal axis 116. The direction 128 is angled between generally sixty degrees and generally eighty degrees away from the reference line 130.

In one enablement of the second expression of the first embodiment of FIGS. 1-4, the direction 128 is more perpendicular to, than along, a reference line 130 which extends from the centerline 122 at the exit 120 to the longitudinal axis 116. In one variation, the direction 128 is angled between generally sixty degrees and generally eighty degrees away from the reference line 130.

In one implementation of the second expression of the first embodiment of FIGS. 1-4, the combustor 110 also includes a straight-flow-combustor inner annular case 132′, a gas-turbine-engine-combustor outer liner 134, and a gas-turbine-engine-combustor inner liner 136, wherein the outer and inner liners 134 and 136 are disposed radially between the outer and inner annular cases 112′ and 132′ and wherein the exit 120 is disposed radially between the outer and inner liners 134 and 136. In one variation, the combustor 110 also includes a plurality of gas-turbine-engine-combustor additional premixer tubes 138 substantially identical to the premixer tube 114, wherein the premixer and additional premixer tubes 114 and 138 are substantially circumferentially arrayed with a substantially equal circumferential distance between adjacent ones of the exits 120 of the premixer and additional premixer tubes 114 and 138. In one modification, the exits 120 of the premixer and additional premixer tubes 114 and 138 are disposed wherein ignition at one of the exits 120 of the premixer and additional premixer tubes 114 and 138 will cause ignition, in sequential rotation, at each of the other of the exits 120 of the premixer and additional premixer tubes 114 and 138.

A first expression of the second embodiment of FIGS. 5-7 is for a gas turbine engine combustor 210 including a reverse-flow-combustor outer annular case 212′ and a gas-turbine-engine-combustor premixer tube 214. The outer annular case 212′ has a longitudinal axis 216. The premixer tube 214 has an entrance 218, an exit 220, and a centerline 222. The premixer tube 214 is adapted to receive fuel-injector-discharged fuel 224. The entrance 218 is adapted to receive at least some compressor-discharge air 226. The exit 220 is disposed inside the outer annular case 212′. At the exit 220 the centerline 222 points in a direction 228 which is more perpendicular to, than parallel to, the longitudinal axis 216. The direction 228 is angled between generally sixty degrees and generally eighty degrees away from the reference line 230.

In one enablement of the first expression of the second embodiment of FIGS. 5-7, the direction 228 is more perpendicular to, than along, a reference line 230 which extends from the centerline 222 at the exit 220 to the longitudinal axis 216. In one variation, the direction 228 is angled between generally sixty degrees and generally eighty degrees away from the reference line 230.

In one implementation of the first expression of the second embodiment of FIGS. 5-7, the combustor 210 also includes a reverse-flow-combustor inner annular case 232′, a gas-turbine-engine-combustor outer liner 234, and a gas-turbine-engine-combustor inner liner 236, wherein the outer and inner liners 234 and 236 are disposed radially between the outer and inner annular cases 212′ and 232′ and wherein the exit 220 is disposed radially between the outer and inner liners 234 and 236. In one variation, the combustor 210 also includes a plurality of gas-turbine-engine-combustor additional premixer tubes 238 substantially identical to the premixer tube 214, wherein the premixer and additional premixer tubes 214 and 238 are substantially circumferentially arrayed with a substantially equal circumferential distance between adjacent ones of the exits 220 of the premixer and additional premixer tubes 214 and 238. In one modification, the exits 220 of the premixer and additional premixer tubes 214 and 238 are disposed wherein ignition at one of the exits 220 of the premixer and additional premixer tubes 214 and 238 will cause ignition, in sequential rotation, at each of the other of the exits 220 of the premixer and additional premixer tubes 214 and 238. In one example, not shown, the premixer and additional premixer tubes have entrances disposed between the outer annular case and the outer liner, have mid portions which loop outside and then re-enter the outer annular case, and have exits disposed between the outer and inner liners.

While the present invention has been illustrated by a description of several expressions of embodiments, it is not the intention of the applicant to restrict or limit the spirit and scope of the appended claims to such detail. Numerous other variations, changes, and substitutions will occur to those skilled in the art without departing from the scope of the invention. 

1. A gas turbine engine combustor comprising: a) a gas-turbine-engine-combustor outer annular case having a longitudinal axis; and b) a gas-turbine-engine-combustor premixer tube having an entrance, an exit, and a centerline, wherein the premixer tube is adapted to receive fuel-injector-discharged fuel, wherein the entrance is adapted to receive at least some compressor-discharge air, wherein the exit is disposed inside the outer annular case, and wherein at the exit the centerline points in a direction which is more perpendicular to, than parallel to, the longitudinal axis.
 2. The gas turbine engine combustor of claim 1, wherein the direction is more perpendicular to, than along, a reference line which extends from the centerline at the exit to the longitudinal axis.
 3. The gas turbine engine combustor of claim 2, wherein the direction is angled between generally sixty degrees and generally eighty degrees away from the longitudinal axis, and wherein the direction is angled between generally sixty degrees and generally eighty degrees away from the reference line.
 4. The gas turbine engine combustor of claim 2, also including a gas-turbine-engine-combustor inner annular case, a gas-turbine-engine-combustor outer liner, and a gas-turbine-engine-combustor inner liner, wherein the outer and inner liners are disposed radially between the outer and inner annular cases and wherein the exit is disposed radially between the outer and inner liners.
 5. The gas turbine engine combustor of claim 4, also including a plurality of gas-turbine-engine-combustor additional premixer tubes substantially identical to the premixer tube, wherein the premixer and additional premixer tubes are substantially circumferentially arrayed with a substantially equal circumferential distance between adjacent ones of the exits of the premixer and additional premixer tubes.
 6. The gas turbine engine combustor of claim 5, wherein the exits of the premixer and additional premixer tubes are disposed wherein ignition at one of the exits of the premixer and additional premixer tubes will cause ignition, in sequential rotation, at each of the other of the exits of the premixer and additional premixer tubes.
 7. The gas turbine engine combustor of claim 6, wherein the outer and inner liners each include a plurality of air dilution holes.
 8. The gas turbine engine combustor of claim 7, wherein the premixer tube is a thermal-barrier-coated tube.
 9. The gas turbine engine combustor of claim 8, also including a combustor dome connecting the outer and inner liners.
 10. The gas turbine engine combustor of claim 9, wherein the combustor dome is a thermal-barrier-coated combustor dome.
 11. A gas turbine engine combustor comprising: a) a straight-flow-combustor outer annular case having a longitudinal axis; and b) a gas-turbine-engine-combustor premixer tube having an entrance, an exit, and a centerline, wherein the premixer tube is adapted to receive fuel-injector-discharged fuel, wherein the entrance is adapted to receive at least some compressor-discharge air, wherein the exit is disposed inside the outer annular case, wherein at the exit the centerline points in a direction which is more perpendicular to, than parallel to, the longitudinal axis, and wherein the direction is angled between generally sixty degrees and generally eighty degrees away from the longitudinal axis.
 12. The gas turbine engine combustor of claim 11, wherein the direction is more perpendicular to, than along, a reference line which extends from the centerline at the exit to the longitudinal axis, and wherein the direction is angled between generally sixty degrees and generally eighty degrees away from the reference line.
 13. The gas turbine engine combustor of claim 12, also including a straight-flow-combustor inner annular case, a gas-turbine-engine-combustor outer liner, and a gas-turbine-engine-combustor inner liner, wherein the outer and inner liners are disposed radially between the outer and inner annular cases and wherein the exit is disposed radially between the outer and inner liners.
 14. The gas turbine engine combustor of claim 13, also including a plurality of gas-turbine-engine-combustor additional premixer tubes substantially identical to the premixer tube, wherein the premixer and additional premixer tubes are substantially circumferentially arrayed with a substantially equal circumferential distance between adjacent ones of the exits of the premixer and additional premixer tubes.
 15. The gas turbine engine combustor of claim 14, wherein the exits of the premixer and additional premixer tubes are disposed wherein ignition at one of the exits of the premixer and additional premixer tubes will cause ignition, in sequential rotation, at each of the other of the exits of the premixer and additional premixer tubes.
 16. A gas turbine engine combustor comprising: a) a reverse-flow-combustor outer annular case having a longitudinal axis; and b) a gas-turbine-engine-combustor premixer tube having an entrance, an exit, and a centerline, wherein the premixer tube is adapted to receive fuel-injector-discharged fuel, wherein the entrance is adapted to receive at least some compressor-discharge air, wherein the exit is disposed inside the outer annular case, wherein at the exit the centerline points in a direction which is more perpendicular to, than parallel to, the longitudinal axis, and wherein the direction is angled between generally sixty degrees and generally eighty degrees away from the longitudinal axis.
 17. The gas turbine engine combustor of claim 16, wherein the direction is more perpendicular to, than along, a reference line which extends from the centerline at the exit to the longitudinal axis, and wherein the direction is angled between generally sixty degrees and generally eighty degrees away from the reference line.
 18. The gas turbine engine combustor of claim 17, also including a reverse-flow-combustor inner annular case, a gas-turbine-engine-combustor outer liner, and a gas-turbine-engine-combustor inner liner, wherein the outer and inner liners are disposed radially between the outer and inner annular cases and wherein the exit is disposed radially between the outer and inner liners.
 19. The gas turbine engine combustor of claim 18, also including a plurality of gas-turbine-engine-combustor additional premixer tubes substantially identical to the premixer tube, wherein the premixer and additional premixer tubes are substantially circumferentially arrayed with a substantially equal circumferential distance between adjacent ones of the exits of the premixer and additional premixer tubes.
 20. The gas turbine engine combustor of claim 19, wherein the exits of the premixer and additional premixer tubes are disposed wherein ignition at one of the exits of the premixer and additional premixer tubes will cause ignition, in sequential rotation, at each of the other of the exits of the premixer and additional premixer tubes. 